The present invention is directed towards electric power handling equipment such as circuit breakers, switchgear, panel boards, motor control centers, busways, etc. More particularly, the present invention is directed toward a system and method for cooling such electric power handling equipment.
Most electric power distribution equipment is rated based on its maximum current carrying capacity. The method of determining this rating is established by industry standards. For example, internal temperature during operation is one of the parameters that may limit the rating a particular piece of equipment is given. Another parameter is the temperature at the customer connection point. In many cases, the physical characteristics of a particular piece of equipment or component thereof would allow higher interruption levels but because of the operating temperature characteristics, the rated level of interruption has to be kept lower.
Because the Underwriter""s Laboratories (UL) code prohibits directly powering internal components with line or load side power, simply adding a fan or cooling unit to the equipment is not always an available option, particularly with circuit breakers.
The use of current transformers (CTs) for sensing current and providing power to controller electronics has been known. However, it has not heretofore been known to use a CT to produce sufficient electricity to power a cooling fan in order to increase the rating of the electrical device by reducing the internal temperature.
The above-discussed and other drawbacks and deficiencies of electrical distribution equipment that generally includes a housing defining an enclosed space and a conductor in the enclosed space are overcome or alleviated by a current transformer utilizing current in the conductor induces current in a secondary winding thereof, and a fan assembly is electrically connected to the secondary winding. The fan assembly includes a fan motor in driving relation to a fan.
The above-discussed and other features arid advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.